PCIEX16 vs PCIEX8

[bennieboi101]

Hey guys i have a question for you all as i am upgrading to dual graphics cards and want a bit of help if possible.

On the motherboard im planning to get it has one PCIEX16 and one PCIEX8. Now it is my understanding that when a card is installed into the PCIEX8 times and shares bandwidth with the PCIEX16 that the PCIEX16 will slow down to x8 speed?

Copied from gigabyte website: The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When PCIEX8 is populated with a PCI Express graphics card, the PCIEX16 slot will operate at up to x8 mode.

So my question is would it be better to get a motherboard with twin PCIEX16 and use those two ports when using dual graphics cards or does it not make that much of a difference. If the performance will be noticeable please mention. Price is not an issues i want the performance, money comes and goes but its not good spending it all if i dont have a massive FPS score.

The two motherboards i was looking at are:

http://www.gigabyte.com.au/products/product-page.aspx?pid=3516#ov PCIEX16 and PCIEX8

http://www.gigabyte.com.au/products/product-page.aspx?pid=3519#ov PCIEX16 and PCIEX16

 

[Lmeow]

There isn't much of a difference between PCI-E x8 or x16 in terms of performance impacts unless you use a card like the HD 5970. It isn't noticeable, so I'd just get the cheaper one. I.e., the GA-890GPA-UD3H.

 

[rolli59]

Here they use HD5870 at different speeds http://www.techpowerup.com/reviews/AMD/HD_5870_PCI-Express_Scaling/25.html